A Kirschner wire (also called a K-wire) is a thin, rigid wire that can be used to stabilize bone fragments in orthopedics and other types of medical and veterinary surgery. Kirschner wires were introduced in surgical procedures by Martin Kirschner in 1909. They are sterilized, sharpened, smooth stainless steel pins and have different sizes. Typical K-wire diameters range from 0.7 millimeters to 1.6 millimeters. Either one or both wire ends are sharpened to a point. Point styles include trocar or diamond points. K-wires can be drilled through the bone to hold bone fragments in place. They are placed percutaneously (through the skin), thus avoiding open surgery in some cases. In other cases, K-wires are used after surgery to hold bone fragments in place. In some cases K-wires include threads for threading into the bone.
In spine surgery K-wires are used as guide wires for the placement of spine fixation components, such as screws and pins. They are inserted either through an open surgical procedure or under fluoroscopic or X-ray observation and are removed after the insertion of the screws. In several instances it is desirable to move the guide K-wires out of line of sight without removing them from the bone locations.